Aluminium nitrate

Endpoint summary

Description of key information

Studies of repeated dose toxiicity are available for the oral route of exposure.  A modern guideline-compliant study performed with a read-across substance provides comparanle results to older published drinking water stuides performed with aluminium nitrate

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published study comparable to guidelines but with investigation of more limited parameters and performed in females only

Qualifier:

no guideline followed

Principles of method if other than guideline:

Groups of tats were exposed to aluminium nitrate via drinking water at three different concentrations for a total of 100 days

GLP compliance:

no

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Interfauna, Spain
- Weight at study initiation: 70.5 +- 4.4 g
- Housing: individually in metabolism cages
- Diet: ad libitum (perfectly balanced Panlab diet, Barcelona, Spain)
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
no data

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Solutions were prepared weekly to adjust the dose to achieve a constant intake. Sugar was added to reduce the aversive effect of the aluminum in the
water (taste). Similar quantities of sugar were also added to tbe drinking water of control animals in order to make comparable the results.

The rats were housed individually in metabolism cages throughout the study and food and waterconsumption ,volume of urine excreted and faecal weight eliminated were measured daily. Bodyweights were recorded weekly and protein efficiency coefficients calculated based on nitrogen ingested and weight gain per unit time.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no data

Duration of treatment / exposure:

100 days

Frequency of treatment:

continuous via drinking water - nominal dose concentrations were 360, 720 and 3600 mg/kg bw/d as aluminium nitrate nonahydrate

Remarks:

Doses / Concentrations:
0, 360, 70, 3600 mg/kg bw/d
Basis:
nominal in water

No. of animals per sex per dose:

10 females per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: doses were selected at 1/10, 1/5 and 1/1 of the acute oral LD50 (gavage)

Positive control:

no data

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes, but not specified

DETAILED CLINICAL OBSERVATIONS: Yes, but not specified

BODY WEIGHT: Yes
- Time schedule for examinations: before the start of the experiment and weekly throughout the 100 days

FOOD CONSUMPTION: Yes, daily

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes, daily

VOLUME OF URINE EXCRETED: Yes, daily

FECES WEIGHT EXCRETED: Yes, daily

CALCULATION OF PROTEIN EFFICIENCY COEFFICIENT: Yes, weekly

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY/CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: blood samples were taken every month and at the end of the experiment
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: 5 animals
- Parameters examined: hematocrit measurements and hemoglobin, plasma levels of glutamic-pyruvic and glutamic-oxalacetic transaminases, alkaline phosphatase, urea, creatinine, uric acid, total protein, cholesterol and glucose

URINALYSIS: Yes
- Time schedule for collection of urine: daily
- Metabolism cages used for collection of urine: Yes
- Animals fasted: No data
- Parameters examined: daily urine volume

OTHER: Aluminum concentrations in brain, heart, lungs, kidneys, liver, spleen, abdominal muscle, bone and blood were measured by atomic absorption spectrophotometry.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes: After 100 days of treatment, the animals were killed and the weight of brain, heart, lungs, kidneys, liver and spleen
measured.
HISTOPATHOLOGY: Yes: Histological tissue examination (paraffin slices, hematoxylin-eosin) was made of heart, liver, kidney, spleen, brain and
cerebellum samples in three rats from each group.

Other examinations:

None detailed

Statistics:

Nutritional parameters, hematological data, clinical chemistry and the concentrations of aluminum were evaluated first by analysis of variance. Any
significant effects disclosed were further analyzed by Student's t-test. In all cases a minimum level of significance of P<0.05 was used.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

effects observed, treatment-related

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No mortality was observed, no data on clinical signs

BODY WEIGHT AND WEIGHT GAIN
A significant decrease in weight gain was observed in the animals of the highest dose group. The animals in the low and mid dose group did not show significant differences in body weights.

FOOD CONSUMPTION
The food consumption was significantly decreased in the animals of the highest dose group.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
The drinking water intake was significantly decreased in the animals of the highest dose group (urinary excretion volume also reduced in this group).

VOLUME OF URINE EXCRETED
The volume of urine excreted was significantly decreased in the animals of the highest dose group.

FECES EXCRETED
The faeces excreted was significantly decreased in the animals of the highest dose group.

HAEMATOLOGY/CLINICAL CHEMISTRY
Only slight variations in some determinations occurred randomly in treated animals (GPT and alkaline phosphatase for the high dose group and urea
for the mid dose group).

URINALYSIS
The volume of excreted urine was significantly decreased in the animals of the highest dose group.
ORGAN WEIGHTS
At the end of the treatment, tbe fresh weight of the organs were measured in ten animals from each group. There were no significant differences between the control and treated groups when expressed relative to body weight.

HISTOPATHOLOGY: NON-NEOPLASTIC
Histological examinations of the various organs showed no anomalies either in the treated animals or in the cantrols. With regard to the bone tissue, it showed a mild hypotrophy upon tbe calcifying cartilage bands of the epiphyseal disk.

OTHER FINDINGS
The concentrations of aluminum in tissues of rats given aluminum nitrate were higher for the treated animals than for the controls. However, no significant relationship between dose and accumulation could be observed.

Dose descriptor:

NOAEL

Effect level:

720 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Reduced body weight (gain), food consumption, water consumption, volume of urine excreted and feces excreted

Dose descriptor:

NOAEL

Effect level:

409 mg/kg bw/day (nominal)

Based on:

other: anhydrous aluminium nitrate

Sex:

female

Critical effects observed:

not specified

Nutritional effects in rats treated with aluminium nitrate in drinking water for 100 days

Dose 0, 360, 720 or 3600 mg/kg bw/d - Al (NO₃)₃.9H₂0

	Study time
	Week 1/2	Week 3/4	Week 5/6	Week 7/8	Week 9/10	Week 11/12	Week 13/14	Week 15/16
Drinking water (mL)
Control	365.0	350.2	355.5	416.7	422.2	477.5	466.7	2853.8
360	325.8*	344.8	357.5	347.7**	317.2***	386.5***	374.7	2454.2
720	301.5**	294.8*	324.2	272.7***	266.2***	271.8***	347.1**	2078.3
3600	155.7***	182.2***	180.3***	223.5***	221.3***	209.0***	184.3***	1356.3
Nitrogen ingested
Control	7.73	8.63	9.33	8.95	8.36	8.87	8.50	60.37
360	6.71*	8.33	8.55	8.54	7.75	7.28	7.89	55.05
720	7.22	8.27	8.28	7.09**	7.29	5.95**	7.41	51.51
3600	5.70***	6.43***	4.74***	6.05***	4.76***	4.22***	4.52***	36.12
Weight gain (g)
Control	71.5	26.9	53.9	6.8	19.4	19.7	8.6	192.2
360	65.9	42.6	44.2	2.7	33.0	18.7	-9.5*	197.6
720	67.8	25.6	42.8*	0.0	20.0	16.0	13.9	186.1
3600	35.3***	26.0	40.4**	3.0	16.3	-13.7***	-7.1**	100.2
PEC
Control	9.2	3.1	5.8	0.8	2.3	2.2	1.0	3.3
360	9.8	5.1	5.2	0.3	4.3	26	-1.2	3.6
720	9.4	3.1	5.2	0.0	2.8	2.7	1.9	3.6
3600	6.2*	4.0	8.5	0.5	3.4	-3.2	-1.6	2.8
Urine excreted (mL)
Control	65.0	99.5	95.8	123.6	153.5	140.8	98.1	776.3
360	50.3	78.3	95.5	92.3*	96.2***	83.3***	88.5	584.4
720	45.0*	65.2*	75.7*	79.8**	76.3***	66.5***	73.8**	482.3
3600	25.3***	30.1***	33.8***	53.3***	47.5***	34.1***	37.0***	262.1
Faeces (g)
Control	64.3	82.0	87.5	81.1	80.3	87.5	84.8	567.5
360	55.3*	78.5	83.1	76.3	81.8	85.2	75.7	535.9
720	54.4**	73.2*	75.8*	72.3	73.5	85.5**	64.7**	489.4
3600	36.8***	53.0***	55.2***	53.4***	50.5***	54.5***	51.2***	354.6
*p<0.05; **p<0.01; ***p<0.001 PEC = protein efficiency coefficient = weight gain/nitrogen divided

 

 

Blood investigations for control and aluminium treated rats exposed over 100 days

 

Blood parameter	Dose (mg/kg bw/d) Al (NO3)3.9H20
	0	360	720	3600
Haematocrit (%)	37	40	35	26
Haemoglobin (g/100 mL)	13.8	15.2	13.0	10.0
GOT (U/l)	158	110	147	163
GPT (U/l)	71	76	80	53*
ALP	145	112	113	231*
Urea (mg/100 mL)	45.8	44.9	62.5*	57.6
Creatinine (mg/100 mL)	1.0	1.1	1.1	1.0
Uric acid (mg/100 mL)	2.4	2.3	2.6	2.1
Total protein (g/100 mL)	9.2	8.2	8.8	7.7
Cholesterol (mg/100 mL)	105	113	102	130
Glucose (mg/100 mL)	106	127	107	109

 

 

Relative organ weights (g/100g BW) for control and aluminium treated rats exposed to aluminium nitrate in drinking water over 100 days

 

Organ weight	Dose (mg/kg bw/d) Al (NO3)3.9H20
	0	360	720	3600
Brain	0.65	0.62	0.64	0.92
Heart	0.32	0.31	0.33	0.35
Lungs	0.60	0.54	0.58	0.68
Kidneys	0.61	0.64	0.66	0.79
Liver	2.89	2.73	2.94	2.70
Spleen	0.16	0.15	0.15	0.21

 

 

Tissue concentrations of aluminium following 100 days administration of aluminium nitrate

 

	Dose (mg/kg bw/d) Al (NO3)3.9H20
	0	360	720	3600
Brain	ND	4.93	2.09	4.28
Heart	1.31	2.19	2.58	4.29
Lungs	ND	28.9	11.5	17.2
Kidneys	0.78	5.20	2.30	3.36
Liver	ND	7.05	3.58	4.66
Spleen	ND	1.67	4.89	4.21
Muscle	ND	1.34	6.58	3.33
Bone	17.15	75.08**	79.18**	56.39**
Blood	ND	ND	ND	ND
*p<0.05; **p<0.01 Limit of detection 0.5 µg/g

 

 

Conclusions:

A NOAEL of 720 mg/kg bw/d (equivalent to 409 mg/kg bw/d anhydrous aluminium nitrate) can be calculated for this study based on bodyweight changes, reduced water consumption and urinary excretion, and effects on nutritional parameters noted at the highest dose level.

Executive summary:

Aluminium nitrate was administered by inclusion in drinking water. Four groups of female Sprague-Dawley rats were treated at 0, 360, 720 or 3600 mg/kg bw/d over a period of one hundred days. Weight gain, food intake, water consumption, haematology and serum chemistry parameters were checked regularly through out the study. Ingestion of aluminium nitrate by rats resulted in significant growth retardation and significantly lower nutritional parameters. Aluminium did not show any dose-related accumulation in any of the organs or tissues examined. No histopathological changes of note were observed and organ weights showed no significant treatment-related changes. A NOAEL of 720 mg/kg bw/d (equivalent to 409 mg/kg bw/d anhydrous aluminium nitrate) can be calculated for this study based on bodyweight changes, reduced water consumption and urinary excretion, and effects on nutritional parameters noted at the highest dose level.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

409 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

A modern guideline-compliant screening study with a read-across substance and two drinking water studies perfomred with aluminium nitrate are available.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In a combined repeated dose / reproductive screening study (OECD 422), administration of the read-across substance aluminium chloride by oral gavage to male and female rats at dose levels of 20, 200 or 1000 mg /kg/d (equivalent to 3.6, 18 and 90 mg/kg bw/d Al) was studied. No toxic effects were observed in females at any dose level. Therefore, the overall NOAEL for female rats was established to be 1000 mg/kg bw/d (equivalent to 90 mg/kg bw/d Al). For males the NOAEL for local effects was established to be 200 mg/kg bw/d (equivalent to 18 mg/kg bw/d Al) based on effects on the stomach and for systemic toxicity 1000 mg/kg bw/d (equivalent to 90 mg/kg bw/d Al; 710 mg/kg bw/d anhydrous aluminium nitrate).

Aluminium nitrate was administered in the drinking water to four groups of ten female rats for one month at dose levels of 0, 375, 750 or 1500 mg/kg bw/d. Appearance, behaviour, food and water consumption and growth were not affected by treatment. Bioaccumulation of aluminium occurred dose-dependently in spleen, heart and gastrointestinal tract. Plasma concentrations showed no effects or signs of toxicity. Mild histological changes were observed in the spleen and liver in the high dose group.

The subacute oral NOAEL was determined to be 750 mg/kg bw/d aluminium nitrate nonahydrate; equivalent to 426 mg/kg bw/d as the anhydrous form.

In a 100 -day drinking water study, four groups of female Sprague-Dawley rats were treated at 0, 360, 720 or 3600 mg/kg bw/d over a period of one hundred days. Weight gain, food intake, water consumption, haematology and serum chemistry parameters were checked regularly through out the study. Ingestion of aluminium nitrate by rats resulted in significant growth retardation and significantly lower nutritional parameters. Aluminium did not show any dose-related accumulation in any of the organs or tissues examined. No histopathological changes of note were observed and organ weights showed no significant treatment-related changes. A NOAEL of 720 mg/kg bw/d (equivalent to 409 mg/kg bw/d anhydrous aluminium nitrate) can be calculated for this study based on bodyweight changes, reduced water consumption and urinary excretion, and effects on nutritional parameters noted at the highest dose level.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Study reporting the lowest endpoint and of the longest duration

Justification for classification or non-classification

The results of the available repeated dose toxicity studies do not indicate any effects sufficient to trigger classification for STOT-RE according to the CLP Regulation.